diff --git a/doc/environments/groupthm/groupthm.dtx b/doc/environments/groupthm/groupthm.dtx
index 8f53e02..0002ac8 100644
--- a/doc/environments/groupthm/groupthm.dtx
+++ b/doc/environments/groupthm/groupthm.dtx
@@ -1842,6 +1842,46 @@
 %    \end{macrocode}
 % \end{macro}
 % 
+%
+%
+% \begin{macro}{\groupthm_add_parent:nn}
+%    \begin{syntax}
+%       \cs{groupthm_add_parent:nn}\marg{theorem group_1}\marg{theorem group_2}
+%    \end{syntax}
+%		 
+%    Declares \meta{theorem group_2} as a parent of \meta{theorem group_1}
+%
+%    \begin{macrocode}
+\cs_new:Npn \groupthm_add_parent:nn #1 #2
+  {
+    \@@_ensure_group_exists:n { #1 }
+    \@@_ensure_group_exists:n { #2 }
+    \clist_gput_left:cn { g_@@_parents_group__#1__clist } { #2 }
+  }
+%    \end{macrocode}
+% \end{macro}
+%
+%
+% \begin{macro}{\AddTheoremGroupParent}
+%    \begin{syntax}
+%       \cs{AddTheoremGroupParent}\marg{theorem group_1}\marg{theorem group_2}
+%    \end{syntax}
+%		 
+%    Document command version of \cs{groupthm_add_parent:nn} 
+%
+%    \begin{macrocode}
+\NewDocumentCommand { \AddTheoremGroupParent } { m m }
+  {
+    \groupthm_add_parent:nn { #1 } { #2 }
+  }
+%    \end{macrocode}
+% \end{macro}
+% 
+% 
+% 
+% 
+% 
+% 
 % \subsection{Iterating over powersets}
 % For generating the different variants of a theorem family,
 % we need to iterate over over the powerset of some list.
diff --git a/doc/environments/groupthm/groupthm.sty b/doc/environments/groupthm/groupthm.sty
index 349a4af..cd68056 100644
--- a/doc/environments/groupthm/groupthm.sty
+++ b/doc/environments/groupthm/groupthm.sty
@@ -369,6 +369,16 @@
   {
     \groupthm_declare_group_rule:nnnn {#1} {#2} {#3} {#4}
   }
+\cs_new:Npn \groupthm_add_parent:nn #1 #2
+  {
+    \__groupthm_ensure_group_exists:n { #1 }
+    \__groupthm_ensure_group_exists:n { #2 }
+    \clist_gput_left:cn { g__groupthm_parents_group__#1__clist } { #2 }
+  }
+\NewDocumentCommand { \AddTheoremGroupParent } { m m }
+  {
+    \groupthm_add_parent:nn { #1 } { #2 }
+  }
 \clist_new:N  \l__powerset_copied_clist
 \seq_new:N    \l__powerset_saved_seq
 \cs_generate_variant:Nn \clist_remove_all:Nn { N V }